Move some Element specific code from Node::detach to Element::detach.

Source/core/dom/UserActionElementSet.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 22 matching lines @@
 namespace blink {
 
 UserActionElementSet::UserActionElementSet()
 {
 }
 
 UserActionElementSet::~UserActionElementSet()
 {
 }
 
-void UserActionElementSet::didDetach(Node* node)
+void UserActionElementSet::didDetach(Element& element)
 {
-    ASSERT(node->isUserActionElement());
-    clearFlags(toElement(node), IsActiveFlag | InActiveChainFlag | IsHoveredFlag);
+    ASSERT(element.isUserActionElement());
+    clearFlags(&element, IsActiveFlag | InActiveChainFlag | IsHoveredFlag);
 }
 
 #if !ENABLE(OILPAN)
 void UserActionElementSet::documentDidRemoveLastRef()
 {
     m_elements.clear();
 }
 #endif
 
 bool UserActionElementSet::hasFlags(const Node* node, unsigned flags) const
@@ skipping 62 matching lines @@
 }
 
 DEFINE_TRACE(UserActionElementSet)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_elements);
 #endif
 }
 
 }